Question

In the figure, the $\angle ABC=30°$. If $CB=18m$ , then AB = and AC = .

• A. $9m$
• B. $9\sqrt{3}m$
• C. $3m$
• D. $3\sqrt{9}m$

Answer 1

Answer: (A), (B)

$9\sqrt{3}m$

Given, $\angle ABC=30°$ and BC = 18 m.

We know that, $sin30°=\frac{1}{2},andcos30°=\frac{\sqrt{3}}{2}$

From the figure,
$sin30°=\frac{AC}{BC}\Rightarrow \frac{1}{2}=\frac{AC}{18}\Rightarrow AC=9m$

Similarly,
$cos30°=\frac{AB}{BC}\Rightarrow \frac{\sqrt{3}}{2}=\frac{AB}{18}\Rightarrow AB=9\sqrt{3}m$